How To: Clean Glazing Putty

You’ve been working hard to reglaze your old windows. You’ve actually used traditional glazing putty instead of caulk like most contractors and now you step back and look at your window and notice that the glass is all oily. What can you do about it? How do you clean glazing putty?

You’re hesitant to grab the glass cleaner and scrub it clean because your glazing putty is still soft and you don’t want to mess up those perfect (kinda) glazing lines. Some folks just give up and wait for everything to cure and then clean the glass a week later when the putty is firm, but this results in dried oils that are a royal pain to remove. There is an easier way!

Professional window restorers use a product called whiting. Whiting is calcium carbonate, or in layman’s terms, chalk dust, like from the black boards in school for anyone born before 1980. Whiting has been used for centuries as a cleaning agent and degreaser for machinery and other industrial needs because it absorbs and carries away oil and grease.

How to Clean Glazing Putty

The oils from glazing putty, typically a mixture of linseed and soybean oils will dry quickly on glass in just a couple hours so it’s imperative to clean things quickly. As soon as you’re done glazing your window you need to clean the glazing putty with whiting to prevent residue on the glass.

Grab a soft bristle paint brush and a container of pure whiting. It’s best to dedicate and paint brush to this purpose and plan on not painting with it again due to the putty and oils that can build up on the brush over time.

Step 1 Apply Whiting

Sprinkle a couple teaspoons of whiting onto the glass and spread it out onto the face of the glazing putty and all over the glass.

Step 2 Brush Vigorously

Using that soft, old paint brush, brush the whiting vigorusly across the surface of the glass and along the surface of the putty. Be careful to have a light tough around the putty to avoid gouging the putty. Keep brushing until the glass comes clean of residue. This will also absorb the excess oils on the face of the putty which whill accelerate the skinning process that needs to occur beforte the putty is ready for paint.

Step 3 Reclaim The Whiting

The excess whiting can then be brushed off the window and even though you won’t get it all back into the container you can save and reuse any that you can finagle back into the container.

Step 4 Clean Remaining Dust

Any remaining whiting on the window can be gentle brushed off the window or blown off using compressed air. Once the glazing putty has cured, usually 3-5 days for Austin’s Glazier’s Putty which is what I use, you can wipe the whole thing down with a damp cloth before painting to seal your glazing putty.

The key is to act early. If you wait more than a few hours or let it sit overnight then this quick trick won’t work and you’ll be left scrubbing and cleaning with a razor blade to get that residue off. Be sure to leave yourself enough time for cleaning glazing putty when you finish glazing your window and you’ll be in much better shape next time.